
In reviewing our replication repository we found an error in the codebooks which we have corrected.
 
In the repository we include codebooks for all data files in the repository. In the codebooks describing the relative exposure statistics for different geographies, we previously described the variable diff.d (which is the difference between republican exposure to democrats and democrats' exposure to democrats) "Relative Democratic Exposure", when in fact it is Relative Exposure for Republicans (i.e. Exposure in the paper is defined in relation to the outgroup, and Relative Exposure for Republicans compares Republican exposure to Democrats to Democratic Isolation). We similarly described diff.r as "Relative Republican Exposure", when it is actually Relative Democratic Exposure.

As such, we have updated the following codebooks to have the proper variable descriptions:

- Codebook-State-relative-exposure-aggregate-data
- Codebook-CBSA-relative-exposure-aggregate-data
- Codebook-County-relative-exposure-aggregate-data
- Codebook-City-relative-exposure-aggregate-data
- Codebook-Zip-relative-exposure-aggregate-data
- Codebook-Tract-relative-exposure-aggregate-data

The updated version of these codebooks, uploaded in January 2024, replaces the initial versions uploaded in January 2015.

These changes are limited to descriptions in the codebook. The code that uses the data and figures and tables in the paper properly describe the variables and analysis.

